A complete vestibular evaluate system including a multi axis vestibular motion system, an eye movement measurement system, an animal stabilization device, a single unit amplifier, and a data acquisition system is requested. The instrument will be utilized by each of the Principle investigators to evaluate vestibular function. The instrument is capable of performing behavioral tests including linear and angular acceleration and off vertical rotary testing. Some investigator and the transgenic core will examine vestibular-evoked eye movements and others will determine the response dynamics of single vestibular afferent nerve fibers. The unit will be housed within the Old Shriner's Hospital at Washington University one floor above the transgenic mouse core and will also serve as a screening device for vestibular deficits in mutant mice. The humans who complain of subjective vertigo or balance difficulties objective vestibular deficits are often subtle and can only be revealed by behavioral tests in a clinical laboratory setting. Eye movements have been extremely useful in this regard. For example, nystagmus produced during head positioning tests is diagnostic for benign positional paroxysmal vertigo and head-thrusting tests can reveal subtle specific semicircular canal dysfunction. Mice lack the capability of speech; therefore if we hope to provide mouse models for specific vestibular defects it is necessary to implement sophisticated tests to document these defects. We desire to standardized the vestibulo-ocular responses to angular and linear acceleration in the mouse. To that end we need a device that can provide specified angular and linear acceleration as well as off vertical axis rotation. Such a platform will enable the evaluation of vestibulo-ocular reflexes over the entire relevant range of frequencies and amplitudes. Further, in the likely scenario of the necessity to test specific therapeutic agents a normative database which to evaluate the action of pharmacological agents will be invaluable. Existing tests such as the vestibular evoked response are not nearly as sensitive as neural recording.